Some pointers for the K100D Super and in general:
Every picture you take is a compromise between 3 variables to get the right amount of light (not too dark and not too light) on the sensor. The variables are: shutter speed, aperture and ISO:
Shutter Speed
This indicates for how long light enters the camera. It is indicated by the number after 'Tv' on the screen on the top of your camera (this number is actually 1/x, so '125' means 1/125th of a second). Too short means your photo will be too dark, too long means it'll be too light (this is also called under- and overexposed respectively).
Another thing to keep in mind with shutter speed is that you can't use a shutter speed too slow because this can cause motion blur. Luckily your camera comes with shake reduction to compensate this a bit. As a rule of thumb, never go below 1/the focal length (the 18-55 and 50-200 on your lenses indicate the focal length). For example, if you're using the 50-200 at 160mm, don't set your shutter speed below 1/160 or you
may experience motion blur. Take a picture at a very slow shutter speed (say, 1/5) and you'll see what I mean.
Aperture
This indicates how wide your lens is opening up. The wider the more light will reach the sensor. It is indicated by the number after 'Av'; the lower the number the bigger the opening. A big opening creates a shallow depth of field. For example, using f4.0 with the 18-55 lens and taking a picture of a flower, the flower will be sharp, but the background will a nice blur (like
this photo). A very small opening (a high number, say f22) creates a very deep depth of field where everything is pretty much in focus. Try taking pictures with these apertures and you'll see what I mean.
Another thing to keep in mind with aperture is sharpness. Lenses are generally at their sharpest between f5.6 and f11. Going bigger than f5.6 may be useful to create the blur as in the picture linked above, going smaller than f11 has very few uses and you probably won't be needing it anytime soon (I've had my camera for over a year and have not yet used it).
ISO
This indicates the sensitivity of the sensor, ranging from 200 to 3200 on the K100D Super. A lower number means the sensor will need more light. The upside of a lower ISO is better image quality. A higher ISO number means you can take pictures when there is less light (such as indoors) but as a result you will get 'noise'. Take a picture with the ISO set to 1600 to see what I mean. On the K100D Super the noise on 3200 is pretty awful (I think) so this setting is best avoided. Keep the ISO as low as you can for the best results. However, if you can't get a fast enough shutter speed it is better to set the ISO higher than to risk motion blur. I would recommend setting the ISO at 200 and changing it when needed.
Other settings
As for mode to use the camera in, I would suggest 'Av'. This mode lets you set the aperture with the scrollwheel, and the camera will set the shutter speed accordingly. This way you have control over the depth of field, a very important creative tool. As you saw with the flowerpicture linked above, a shallow depth of field gives a very nice effect. It points out what the subject of the photo is and this is pleasant for the eyes to look at. If the above picture was taken with a small aperture (such as for example f22), the leaves and other plants in the background would be in focus as well, resulting in a very chaotic image.
Do keep an eye out for the shutter speed the camera chooses though, as to avoid motion blur. If the shutter speed is too slow, choose a bigger aperture (lower number) or change the ISO.
The button next to the shutter release button, the square one with the '-' and '+' and with 'Av' next to it, you use to make the picture darker or lighter if the camera for some reason chooses a setting that results in an under- or overexposed photo. You press it and simultaneously turn the scrollwheel (in manual mode you use this button to change the aperture).
This is useful for situations when you're taking pictures with alot of light or dark colours, such as for example snow or a black pet. In the example of the snow, what happens is that when the camera sees alot of white it'll think the picture is too light. It will then compensate for this resulting in snow that is not white but a light shade of grey. To get the camera to exposure correctly in this situation you set the camera to overexpose. To get the camera to exposure correctly in a situation with alot of dark colours (such as a black pet) you set the camera to underexpose. Try this out and you'll see what I mean.
The white balance you can keep on auto. The camera will choose the correct while balance so this is one less thing for you to worry about. One tip for sunsets: set the white balance to 'daylight'. This way the amazing colours of a sunset are not compensated by the camera.
With a tripod you can take pictures with very slow shutter speeds. You may want to bring a small one for the occasional picture you'll be taking at night (I can imagine Venice by night is beautiful). When shooting with a tripod turn off Shake Reduction and turn on the 2 seconds self-timer (accesible through the 'Fn' butter and then the menu accessed by the 'above'-arrow).
Post your Photos!
Finally, the best thing about these forums is the Post your Photos! section:
Post your photos! - PentaxForums.com . Here you can show your fellow Pentaxians (yes, this is your new name) and get comments and critiques to improve them. The #1 tool to improve your technique.